This invention relates to the art of effecting and controlling the inflation, deflation and gauging of pneumatic tires on a vehicle and, more particularly, to an improved method and apparatus by which such functions are achieved.
It is well known to provide vehicles with onboard systems and apparatus enabling the vehicle operator to inflate, deflate and/or check the pressure of the vehicle tires with the vehicle at rest or in motion. Such systems and apparatus include a source of air under pressure carried on the vehicle, and valving and sealing arrangements for delivering air to the vehicle tires to inflate the latter, for venting air from the tires when it is desired to reduce the pressure therein, and for connecting the system in a closed mode to an appropriate gauge indicating the tire pressure.
Systems and apparatus heretofore provided for achieving the above functions have been structurally complex and thus both more costly and less efficient and dependable in operation than desired and, in some instances, have necessitated mounting of component parts of the apparatus and system in locations on the vehicle in which the parts are undesirably exposed to damage, such as on the outer ends of the wheel hubs. A major disadvantage in the apparatus and systems heretofore provided resides in the fact that sealing components required between fixed and rotating parts of the wheel assembly to facilitate the delivery of air therebetween constantly engage the rotating part and thus are continuously subjected to wear which reduces seal life and increases down time and maintenance costs. Moreover, the seals are sometimes subjected to constant air pressure from the system which further increases seal wear. Moreover, such sealing arrangements trap moisture in areas of the wheel assembly and thus promote corrosion problems in such areas. Other problems result from the provision of air flow passageways through axle components of the vehicle, which passageways either reduce the strength of the axle or requires a larger structure to assure a desired strength.